Synthesis of flake-like graphene from nickel-coated polyacrylonitrile polymer

Hwang

Applied Physics Letters

et al. 2015

We investigated a bilayer catalyst system consisting of polycrystalline Ni and W films for growing mono-layer graphene over large areas. Highly uniform graphene was grown on Ni/W bilayer film with 100% coverage. The graphene grown on Ni/W bilayer film and transferred onto an insulating substrate exhibited average hole and electron mobilities of 727 and 340 cm2V−1s−1, respectively. A probable growth mechanism is proposed based on X-ray diffractometry and transmission electron microscopy, which suggests that the reaction between diffused carbon and tungsten atoms results in formation of tungsten carbides. This reaction allows the control of carbon precipitation and prevents the growth of non-uniform multilayer graphene on the Ni surface; this has not been straightforwardly achieved before. These results could be of importance in better understanding mono-layer graphene growth, and suggest a facile fabrication route for electronic applications.

mentioning

confidence: 99%

Growth of ultra-uniform graphene using a Ni/W bilayer metal catalyst

Hwang

Applied Physics Letters

et al. 2015

Chemical Vapor Deposition for Nanotechnology

“…The catalyst plays an important role in the CVD process. We generally use Cu [5,24,25], Ni [6,23], Pd [49], Ru [57], and Ir [58], as the metal base material for the preparation of graphene. As we know, different metal base materials have a different effect on the preparation of graphene, so the metal substrate is the key factor to determine the growth of graphene.…”

Section: Choice Of Metal Base Materialsmentioning

confidence: 99%

“…Compared with other methods, such as mechanical exfoliation of graphite [12][13][14], liquid-phase exfoliation [15,16], and reduction of graphene oxide (GO) [17,18], chemical vapor deposition (CVD) is regarded as the most promising way for large-scale graphene production at a large scale with low defects, good uniformity, and controlled number of graphene layers, which has attracted intense research attention during the last decades [19][20][21][22]. CVD involves the activation of gaseous reactants and the subsequent chemical reaction, followed by the formation of a stable solid deposit over a suitable substrate such as Ni [6,23], Cu [5,24,25], Fe [26], Pt [27,28], or their alloys [29,30]. As early as 1969, Robertson et al [31] discovered that chemical vapor deposition in the presence of methane produces a layer of graphite on some transition metal surfaces.…”

Section: Introductionmentioning

confidence: 99%

Large-Area Synthesis and Growth Mechanism of Graphene by Chemical Vapor Deposition

Wang¹,

Vinodgopal²,

Dai³

2019

There has been continuous progress in the development of different synthesis methods to readily produce graphene at a lower cost. Compared with the other methods, chemical vapor deposition (CVD) is an effective and powerful method of producing graphene and has attracted increased attention during the last decade. In this way, we can obtain good uniformity with a multitude of domains, excellent quality, and large scale of the produced graphene. Meanwhile, it is also helping for large-area synthesis of single-crystal graphene. In the CVD method, precursors are typically absorbed on the surface followed by pyrolytic decomposition, which leads to the generation of absorption sites on the surface and promotes the growth of continuous thin films.

“…Considering Ni NPs as a filler for carbon structure is an important and interesting issue because nickel–graphene structures are regarded as promising advanced materials. Ni by itself was successfully used for the catalysis of carbon polymorphs growth [16, 17], fabrication of new carbon configuration like nanoscrolls [18, 19], transformation of graphene to fullerenes [20] to name a few. Addition of Ni to the carbon structure can considerably improve the properties of the resulting material.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation of fabrication of Ni‐graphene composite: temperature effect

Safina

Baimova

2020

Micro & Nano Letters

Fabrication of Ni-graphene composite by hydrostatic pressure at finite temperatures or by the subsequent annealing is studied by molecular dynamics simulation. Crumpled graphenethe network of folded and crumpled graphene flakes connected by van-der-Waals bondsis chosen as the matrix for Ni nanoclusters. It is found that hydrostatic compression at zero or room temperature cannot lead to the formation of the composite structure. Even strongly compressed crumpled graphene after unloading returned to the initial state of separated graphene flakes. However, annealing of the compressed structure at high temperature leads to the appearance of the valent bonds between neighbouring flakes. Simultaneously, hydrostatic compression at high temperature between 1000 and 2000 K leads to the better mixing of Ni atoms inside the structure and to the formation of strong covalent bonds between neighbouring flakes.